JPS5823859B2 - 2↓-ta↓-shari↓-method for producing alkyl-substituted anthraquinone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for making 2-tertiary-alkyl substituted anthraquinones.

General formula [wherein R1 and R2 represent a hydrogen atom or a tertiary alkyl group; when one is a tertiary alkyl group, the other is a hydrogen atom; and R3 is an alkyl group having 1 to 3 carbon atoms. Indicates the group.

] A diphenylmethane type compound represented by is oxidized in gas phase in the presence of a catalyst containing a vanadium compound,
A method for producing 2-tert-alkyl-substituted anthraquinones is shown in Japanese Patent Application Laid-Open No. 52-3047.

The present inventors further studied the vanadium-based catalyst used in this method, discovered a new vanadium-based catalyst with excellent activity and life, and arrived at the present invention.

That is, in JP-A-52-3047, there is almost no formation of benzylbenzaldehyde type compounds (
It is disclosed that the desired 2-tertiary-alkyl-substituted anthraquinone can be obtained in good yield, and a vanadium-based catalyst consisting of vanadium oxide alone or in combination with another metal-containing compound is taught as a gas-phase oxidation catalyst. ing.

As a result of further studies on this vanadium-based catalyst, the present inventors found that a catalyst consisting of a combination of vanadium and cerium not only promotes the gas phase oxidation more suitably and provides the target product in a high yield, but also catalyzes It has been found that the activity of the compound remains stable over a long period of time.

Therefore, the present invention provides a highly practical method for producing 2-tertiary-alkyl-substituted anthraquinones in high yields without catalyst replacement over long periods of time.

In carrying out the method of the present invention, the catalyst used must contain vanadium and cerium elements,
Vanadium and cerium are usually used as catalyst components in the form of oxides.

The composition ratio of vanadium and cerium is V:Ce in atomic ratio.
-100:22 to 60, preferably 100:6 to 40.

Although these catalyst components may be used as a catalyst by X-molding as they are, it is usually preferable to support them on an inert carrier such as fused alumina, silicon carbide, or aluminum sponge.

In the method of the present invention, the diphenylmethane type compound that can be used as a raw material is represented by the above general formula, and specifically, 4-t-butyl-2-benzyltoluene, 5-t-butyl-2-benzyltoluene, 5-t-
-7” thyl-2-benzyltoluene, 4-t-amyl-
2-benzyltoluene, 5-t-amyl-2-benzyltoluene, 4-t-phthyl-2-benzylethylbenzene, 5-butyl-2-benzylethylbenzene, 4
-t-amyl-2-benzyl-ethylbenzene, 5-t
-Amyl-2-benzylethylbenzene, 4-t-butyl-2-benzylcumene, 5-t-butyl-2-benzylcumene, 4-t-amyl-2-benzylcumene, 5-
Examples include t-amyl-2-benzylcumene.

The diphenylmethane type compound, which is a raw material, is vaporized, mixed with air, and introduced into a reactor filled with the vanadium-cerium catalyst to be oxidized.

The raw material compound is contained in the feed gas introduced to the catalyst layer at a concentration of 0.1
It should be mixed with air to contain a concentration corresponding to ~2 mol%.

The gas containing the raw material has a space velocity of 2000 to 15000 Hr.
', preferably in the range of 3,000 to 10,000 Hr-1.

The reaction temperature is controlled to be maintained at 350-450°C.

The reaction according to the method of the present invention can be carried out without any problem under normal pressure, increased pressure, or reduced pressure.

The reaction product after the catalytic oxidation reaction is directly condensed with X or absorbed in an organic solvent, and then the target product is separated and obtained from the reaction product by known means such as distillation or crystallization.

Next, the details of the present invention will be explained with reference to examples.

Comparative Example 1 V shown in Example 2 of JP-A-52-3047
A life test was conducted on a catalyst containing -T i -Cs.

The catalyst was prepared as follows according to the example.

Ammonium metavanadate 12.87P to water 150P
ml, add 26 g of oxalic acid trihydrate to 8
Heated to 0-100°C to obtain a blue solution.

To this, titanium tetrachloride 1.0 (1, cesium chloride 0.
355′? (stir), then add 50 M' of fused alumina (average diameter: 3 mm) and evaporate to dryness on a water bath to adhere the catalyst component to the alumina.

After pre-drying this at 180°C for 10 hours, it was filled into a stainless steel firing tube and fired at 500°C for 3 hours under air circulation.

The active component composition of the obtained alumina supported catalyst was V:Ti:
Cs (atomic ratio) was -100:5:2.

This catalyst was packed into a stainless steel reaction tube, and a raw material mixture of 4-t-amyl-2-benzyltoluene (90 mol%) and 5-t-amyl-2-benzyltoluene (10 mol%) was vaporized into air. Mix this with 5V3000hr
', the reaction was continued by passing through the catalyst layer at an oxidizing raw material concentration of 0.2 mol%.

Table 1 shows the relationship between reaction time and 2-t-amyl anthraquinone yield.

The reaction temperatures shown in Table 1 indicate the optimum temperatures for the corresponding reaction times.

From this table, it can be seen that the activity of the catalyst decreases slightly after 10 hours.

Example 1 Add 150ml of hydrochloric acid to 10g of vanadium pentoxide,
Heating to 60-80°C gave a dark green solution.

To this was added 3.85 S' of cerous nitrate hexahydrate and stirred to obtain a homogeneous solution.

This solution was sprayed onto 500 g of fused alumina heated to 180° C. to uniformly adhere the catalyst component to the surface of the carrier.

The obtained catalyst was packed in a stainless steel tube and placed under air circulation for 5 minutes.
It was baked at 00°C for 3 hours.

The effective component composition ratio of the obtained alumina supported catalyst was V:Ce
-100:12 (atomic ratio).

This catalyst was packed into a stainless steel reaction tube, a raw material mixture of 4-t-amyl-2-benzyltoluene (90 mol%) and 5-t-amyl-2-benzyltoluene (10 mol%) was vaporized, and air and passed through the catalyst bed under the following reaction conditions to obtain the following reaction results.

Reaction conditions: Reaction rate 420°C Space velocity (SV) 3000 hr'
Raw material concentration 0.2 mol% Reaction result (reaction result 5 hrs after the start of reaction): Raw material conversion rate
98.7% 2-t-aminoanthra 54.6% (or 7.) quinone yield Example 2 The catalyst used in Example 1 was directly subjected to the X reaction.
The catalyst life test was carried out continuously for 000 hours, and the results shown in Table 2 were obtained.

It can be seen that the catalytic activity lasts for an extremely long time.

Examples 3 to 5 V-Ce with different composition ratios prepared in the same manner as Example 1
Raw materials of 4-t-amyl-2-benzyltoluene (88 mol%) and 5-t-amyl-2-benzyltoluene (12 mol%) were prepared using an alumina-supported catalyst under the same reaction conditions as in Example 1. The mixture was oxidized and the results shown in Table 3 were obtained.

Claims (1)

[Scope of Claims] 1 General formula [wherein R1 and R2 represent a hydrogen atom or a tertiary alkyl group, and when one is a tertiary alkyl group, the other is a hydrogen atom, and R3 represents an alkyl group having 1 to 3 carbon atoms. A method for producing a 2-tertiary-alkyl-substituted anthraquinone, which comprises gas-phase oxidation of a diphenylmethane compound represented by the following formula in the presence of a catalyst containing vanadium and cerium.